Osmotic Power: Scientists Develop Electricity From Water, Salt, Thin Membrane

A team of scientists has generated a way to harness clean renewable energy. Dubbed osmotic power, it comes from a natural phenomenon when freshwater comes in contact with seawater through a very thin membrane.

According to the research published in the journal Nature, scientists at the Ecole Polytechnique Fédérale de Lausanne's Laboratory of Nanoscale Biology has created an innovative way of yielding more osmotic power by using a three-atom-thick semipermeable membrane, which separates the seawater and fresh water depending on salt concentration. The system then balances these salt concentrations until they reach equilibrium.

Made of molybdenum disulfide, the membrane has a nanopore where seawater and freshwater could pass through until they balance out.

Jiandong Feng, lead author of the research, said they had to be precise with the size of the nanopore as making it too big will result to lower voltage, while making it small will hinder the ions to pass through.

"We had to first fabricate and then investigate the optimal size of the nanopore. If it's too big, negative ions can pass through and the resulting voltage would be too low. If it's too small, not enough ions can pass through and the current would be too weak," Feng said.

Science Daily notes that the discovery could open doors to new energy alternatives. The team has estimated that osmotic power created from a 1m² membrane is enough to generate 50,000 standard energy.

This revolutionary discovery also creates great potential for estuaries as energy resources. There have been pilot projects conducted in the U.S., Netherlands, Japan and Norway.

What makes osmotic power different from other types of renewable energy, such as solar and wind energy, is that it could produce energy regardless of time, weather and situation.

The scientists hope that a more powerful osmotic power could be developed to make renewable energy more accessible.